Both have elected for mid-February unveils, with Renault peeling back the covers of the RS18 on February 20.
It's the same day that Sauber has elected to reveal its new car, the C37, with both teams opting for low-key, online launches.
Entering its third season back in Formula 1, Renault finished the 2017 campaign sixth in the constructors' championship, narrowly beating Toro Rosso and Haas in a tight midfield battle, but some distance from fifth-placed Williams.
It has also inked an improved deal with Ferrari that will see it receive current-spec engines, part of its estimated £20million naming rights sponsorship deal with Alfa Romeo, as opposed to the year old units it was blighted with last season.
Red Bull and Haas remain the only two teams yet to confirm when they'll launch their 2018 cars.
The opening pre-season test gets underway in Barcelona on February 26.
2018 Formula 1 Launch Dates
|Alfa Romeo Sauber